


World of Two

by alenie



Category: Teen Wolf (TV)
Genre: Accidental Voyeurism, Future Fic, M/M, Semi-established relationship, Voyeurism, slight AU
Language: English
Status: Completed
Published: 2012-11-24
Updated: 2012-11-24
Packaged: 2017-11-19 10:42:05
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,608
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/572389
Author URL: https://archiveofourown.org/users/alenie/pseuds/alenie
Summary: <blockquote class="userstuff">
              <p>And Stiles was laughing, out of breath and panting as he darted across the living room. He had only made it five steps inside the house when the door banged open again and Derek flew in, hot on Stiles’ heels.</p>
            </blockquote>





	World of Two

The phone rang. And rang. And rang. Isaac shifted back and forth impatiently. It was cold outside the diner, and he was hungry, and Scott was late.

At last, Scott picked up.

“Hello?” he said, in that rushed, confused way that people do when they only just make it to the phone and don’t bother checking the caller ID before they answer.

“You were supposed to meet me half an hour ago. Where are you?”

“Oh,” Scott said, and his voice still had a peculiar breathy, rushed quality to it. “Isaac! Sorry, man, I totally forget. I’m-”

“With Allison,” Isaac finished, because he could hear Allison in the background, and it suddenly became horribly clear why Scott sounded so weird. _Ew._

“Uh, yeah. She, um, needed my help with something, and then I guess it just slipped my mind that we were gonna meet up? I can totally still meet you though, if you just, like, give me twenty minutes-”

There was a muffled noise, which must be Scott covering the receiver, and then a faint sound of talking. Isaac couldn’t pick up what they were saying.

“Scott?”

“Yeah? Look, I’ll be there, it’s cool-”

Isaac sighed.

“Just stay at Allison’s. It’s okay. We’ll reschedule.”

“Really? You don’t mind? Man, you are the best, okay? Seriously.”

“Later,” Isaac said, and hung up. It wasn’t that he didn’t mind. He didmind. A lot. He’d been forgotten about enough for one lifetime already and he’d thought maybe, just maybe, now that he was part of something bigger, part of a _pack_ , it’d be different. And for the most part, that was true. He didn’t share Erica and Boyd’s close bond, but at the very least Derek made him feel wanted, even needed, and that was a hell of a lot more than he could say about his own father.

Whatever, it was stupid to get upset about this. He knew Scott was so infatuated with Allison that he’d forget his own brain if he had the chance. He was a hopeless case. (Yes, Isaac had heard the story of how Stiles nearly had to saw off Derek’s arm because Scott was taking his sweet sweet time helping them.)

Anyway, where the fuck was he going to go now? He was still hungry, but he didn’t want to go to the diner by himself, and he couldn’t go home because he lived with Scott now. After Melissa found out about A) the existence of teenaged werewolves, B) that Isaac was one such werewolf, and C) that he’d been living, for the most part, in an abandoned subway station with Derek, she’d practically forced Isaac to move in with them. (Well, first she’d been very, very upset, but she’d acclimated surprisingly quickly.) They had a spare room- their house was _huge_ , Isaac still wasn’t sure how they could afford to live there- and Isaac had moved in a few months ago. But it was still Scott’s home, in the end, and he didn’t want to go there while he was upset with him. It didn’t feel right.

Stiles was supposed to get back today from a two-week long vacation with his father. He’d let Isaac crash at his place, if he asked, and while Isaac wouldn’t have hesitated if they were closer, the truth was that he didn’t know Stiles that well, despite being on the same lacrosse team. Stiles and his dad would be settling back in from their trip and Isaac shouldn’t intrude on that.

That left Derek’s. Derek had finally gotten his act together three or four weeks ago and rented a tiny house on the outskirts of town, right up against the woods. Isaac had wanted to ask why Derek hadn’t done it earlier, if he’d had the money for it all along. But the only time he’d tried, Stiles had been there, and he’d taken Isaac aside and made it clear that he should steer away from that line of questioning if he wanted to stay on Derek’s good side (or should that be less-bad side? If Derek had a good side, Isaac hadn’t seen it yet).

The point was that Isaac had a key to Derek’s place. 

Technically, it was supposed to be for emergencies only, but Derek probably wouldn’t mind. Maybe he’d even be there, and then he could let Isaac in and he wouldn’t have to use his key and they could hang out and maybe even order some food. 

It was a forty-five minute walk there. He could have gotten there much faster if he’d run, but Isaac didn’t mind. Walking warmed him up enough that he wasn’t cold, and the air was crisp and invigorating. Most of the leaves had fallen off the trees by now, blanketing the sidewalks. Isaac made a point of trying to step on all the ones that looked like they would crunch nicely. 

The house was dark and no one answered when Isaac knocked on the door. He tried the knob and found to his surprise that it was unlocked. He pushed the door open and tentatively stepped inside. 

“Derek?” he called. No answer. That was odd. All things considered, Derek tended towards an understandable paranoia, and it wasn’t like him to leave his home open to potential intruders. That probably meant he’d be back soon. Isaac might as well stick around and wait for him to show up. 

He didn’t bother turning any of the lights on. The last vestiges of light from the setting sun were more than enough for werewolf eyes to see by. 

He wandered into the kitchen and went around opening cupboards and checking out the contents of Derek’s fridge. It turned out that Derek had all the necessary sandwich making supplies, so Isaac fixed himself a huge turkey sandwich with tomato and mozzarella cheese and took it into the living room. The last time they’d gotten together as a pack, it’d been here, and that was when Isaac had discovered his favorite feature of Derek’s house: the living room window seat. Someone (Isaac didn’t think it was Derek; Derek didn’t strike him as much of a home decorator) had seen fit to line it with multitudes of squishy pillows and it was basically the most comfortable seat in the entire house. There was even a set of curtains that could be drawn to separate it off from the rest of the room. 

Isaac polished off the sandwich in a matter of minutes, watching as the sun sank down behind the trees. There was still no sign of Derek. He put down his plate and curled up among the cushions. It wouldn’t do any harm to take a nap while he waited for Derek to get back. 

With his face in the cushions, he was confronted by a weird smell. Like Derek and then…not like Derek. The scents were mixed together. It was a familiar smell, but not one he could place, because Isaac wasn’t really that good at identifying smells yet. He knew Derek’s, because Derek was his alpha, and he knew Scott’s because they lived together, and that was pretty much it. This smell wasn’t as strong as Derek’s, but it wasn’t by any means faint. Whoever it belonged to was a regular visitor here. 

Which was just baffling, if you asked him. Isaac hadn’t realized Derek had any friends. Mostly Derek had enemies, and lots of them. 

He fell asleep still wondering who the mysterious scent belonged to, and woke abruptly some time later. He didn’t hear any noise in the house, but he felt on edge with the knowledge that _something_ had woken him. He concentrated and realized that he could hear the sound of running footsteps outside- make that two sets of footsteps- quickly growing louder as they got closer to the house. Isaac looked out the window, but the angle was all wrong and he couldn’t see anything. 

Before Isaac could decide what he ought to do, the front door burst open. He crouched back behind the mounds of pillows and peeked out through the slit in the curtains, glad he’d drawn them before he’d fallen asleep. 

 His fangs had started to descend automatically, triggered by stress, when the same strangely familiar smell from before hit his nose, only more concentrated now, and strong enough for Isaac to read. It was _Stiles’_ scent. 

And Stiles was laughing, out of breath and panting as he darted across the living room. He had only made it five steps inside the house when the door banged open again and Derek flew in, hot on Stiles’ heels. Stiles looked back over his shoulder as he scrambled past the coffee table and Isaac watched as Derek growled and pounced, leaping over the table and tackling Stiles down onto the ratty old couch. Stiles shrieked and then broke out again in bright, sharp peals of laughter. 

Isaac knew he should come out from behind the curtain- but instead he stared, transfixed, as Stiles pulled Derek closer and wrapped his arms around Derek’s neck, grinning up at him. 

No. No way. Stiles and Derek? Because that looked an awful lot like _Stiles and Derek_ , and Isaac _really_ needed to let them know he was here, like right now. 

“Hey stranger,” Stiles was saying. “What’s a good-looking werewolf like you doing in a place like this?” 

Derek snorted. “You’re ridiculous,” he said, and even Isaac could read the affection in his tone. 

“I’m whatever you want me to be, baby.” 

“Please never say that again.” 

“Make me,” Stiles said. “Because you know I can- _oh._ ” 

Derek’s face was hidden in the curve of Stiles’ neck, but the way Stiles arched up in response to whatever Derek had done was unmistakable. 

“Yeah,” Stiles breathed out, voice gone low and husky. One of his hands slid up and buried itself in Derek’s hair, urging him on. 

Derek dipped his head again and Stiles let out a breathy moan and tilted his head back, exposing the long, pale length of his neck. 

_I should close my eyes_ , Isaac thought. _I shouldn’t be watching this_. And yet he couldn’t look away. 

He kept watching as Derek shifted over Stiles and insinuated a knee between Stiles’ legs. Stiles opened for him easily, spreading his legs to let Derek settle down between them. Derek kissed his way up Stiles’ throat to his mouth, and then they were trading some of the most obscene, open-mouthed kisses that Isaac had ever witnessed outside of pornography. These kisses were full-body affairs, Stiles pushing his hips up as Derek pushed down, both of them gasping around the wet press of their mouths. 

Isaac was getting hard. 

Undeniably, undoubtedly hard. 

He couldn’t help it, not with the way Stiles was squirming under Derek. And those _noises_ ; it was like they went straight to his dick. His jeans were already nearing the point of uncomfortable tightness. He was palming himself through the denim, trying to rearrange things into a less constricting position, when he heard Stiles moan. Isaac looked up just in time to see Derek’s hand slide up under Stiles’ shirt. Isaac’s grip on himself instinctively tightened and he had to bite his lip to keep from making noise. 

Ever so slowly, he thumbed open the button of his jeans and lowered the zipper, near shaking from fear of being caught out and guilty excitement. Thankfully, it seemed that Derek was too preoccupied to notice Isaac. After all, he hadn’t even smelled Isaac when they came in. The whole room already reeked of arousal- it probably masked his scent. 

Derek and Stiles were still kissing, but they’d backed off, their initial burst of frantic sexual energy mellowed down into something quiet and intimate. Stiles’ shirt was pushed up high on his chest, and his pale skin shone in the dimly lit room. 

“Take this off,” Derek said, and pulled at the shirt until Stiles lifted his arms and let Derek strip it off him. 

“Yours too,” Stiles urged, and Derek yanked off his own shirt. For a moment he just sat there, kneeling between Stiles’ thighs, gazing down at him. Then Stiles shivered and tugged at Derek’s arm. 

“Come back here,” he said, and Derek went willingly, blanketing Stiles with his body. They went back to kissing leisurely, hands tracing patterns on each others’ skin, until Stiles did something that Isaac couldn’t see, something that made Derek arch up and then push back down into Stiles’ touch. 

“You like that?” Stiles asked. “Can I, um, Derek, can I-” 

“Tell me,” Derek said. 

“Can I suck on your nipples?” Stiles blurted out. “Would- is that something you’d like?”

 _Fuck_. Isaac couldn’t take it anymore. He’d been trying not to touch himself- that seemed like it might be crossing some sort of line- but his dick was tenting the front of his boxers and he really, _really_ needed to touch it. He pushed his jeans down his hips and carefully pulled his boxers up and away from his dick, watching as it bobbed into view, red and standing at attention. He licked over his hand and gave his erection a tentative stroke. God, that felt good. 

He heard muffled sounds of movement, and glanced up to see Derek and Stiles rearranging themselves so that Stiles was on top, perched on Derek’s hips. 

“Okay,” Stiles said. “I’m just, I’m going to-” and he bent down and took one of Derek’s nipples into his mouth. Derek’s reaction was immediate. His mouth fell open and his hands cupped the back of Stiles’ head, much like Stiles had done to him earlier. 

Stiles pulled off with a wet smack. 

“You like that, huh?” 

“Stiles, fuck. Your _mouth_ ,” Derek said, and Stiles grinned and scraped his teeth against the stiff point of Derek’s nipple, drawing an unsteady groan out of Derek.

Isaac watched as Stiles licked and sucked and bit until Derek’s nipple must have been red and sore and shiny, wet from Stiles’ spit. He licked a path across Derek’s chest to his other nipple and repeated the process as Derek fell apart under him. 

“ _Stiles_ ,” Derek begged eventually, and pulled Stiles up to get at his mouth, kissing him soundly. “I want to touch you, take off all your clothes. Can I?” 

“Christ, Derek, yes, of course you can.” 

Derek’s hands went immediately to Stiles’ belt, unbuckling it and then undoing Stiles’ jeans. He pushed them down Stiles’ hips, and Stiles tried to help take them off, and they ended up in a complicated tangle of bodies and pants, which resolved itself into Stiles sprawled back against the couch and Derek _on his knees_ on the floor in front of him.

Stiles was wearing tight-fitting dark blue briefs that did absolutely nothing to conceal the heavy length of his dick. Isaac expected Derek to take those off of Stiles too, but instead Derek leaned forward and mouthed at Stiles through the cotton, his hands on Stiles’ hips, keeping him pinned to the couch. Derek ran his mouth up and down Stiles’ dick unhurriedly, getting the fabric good and wet while Stiles writhed under him.

So it turned out that Stiles had a really nice dick. 

When at last Derek tugged the briefs off, Isaac got a good long look at it. It was nicely shaped and of a decent length, if not overly thick. It fit well with the rest of his body, with his height and his agile hands and his skinny fingers. 

Derek went straight to Stiles’ balls, licking and mouthing at them. By the time he moved to his cock, Stiles was panting and trying to move under Derek’s hands, jerking his hips in fruitless little motions. Derek took his time blowing him, starting out with short, teasing licks. When he took Stiles into his mouth, he spent several long minutes just on Stiles’ cockhead alone, sucking on it like he had all the time in the world, while Stiles said his name over and over, pleading for more. Isaac noticed that one of Derek’s hands was now out of sight, and gaped in wonder when he realized that Derek had snuck a hand off of Stiles’ hip in order to press it against the front of his own jeans. Because that meant… 

That meant Derek was getting off on having Stiles’ cock in his mouth. 

Stiles noticed too. “Yeah,” he said. “Touch yourself. I wanna see.”

Derek’s back was blocking Isaac’s view, but Isaac could tell when Derek got a hand on his dick from the steady up-down movement of his arm. 

He took Stiles’ cock in deep, and then deeper, until his nose was nearly pressed against the dark hair of Stiles’ groin, the muscles in Derek’s throat working as he swallowed around the length of Stiles’ dick.  

Stiles looked like he was about to come. His face was flushed red and his hands were fisted against the fabric of the couch, his mouth hanging open- and then Derek pulled off. 

“Can I fuck you?” Derek asked hoarsely. 

Stiles didn’t hesitate.

“Oh my god, yes. A million times yes. I want you inside me like, all the time, you don’t even know.” 

“Yeah?” Derek said. “You like it that much?” He ran his hands up the insides of Stiles’ thighs. “Tell me how much you want it,” he said, and to Isaac’s ears, it sounded more of a plea for reassurance than anything else. 

“I want it so much,” Stiles said, cupping Derek’s face. “The first time you fucked me, christ, it was the best thing that’d ever happened to me.” 

Derek turned and kissed Stiles’ palm, then his knee. He made his way up Stiles’ thigh and when he got to the crease of thigh and crotch he pushed Stiles’ legs up until Stiles hooked his arms under his knees and held them up and out of the way, exposing his asshole to Derek. Derek stroked across it gently, rubbing circles into it with his finger, pressing against it but not quite pushing in, testing the give of the muscle.

“Jesus fuck Derek, lube, where is your lube? Is it still in the window seat from last time?” 

Isaac’s first thought was _woah, they fucked in the window seat_? Quickly followed by _oh shit, I’m about to get found out and Derek’s going to_ kill _me.  
_

“No, I moved it,” Derek said, and Isaac collapsed back in relief as Derek half-turned and fumbled under the coffee table. 

“God, you totally stashed it there, didn’t you? You planned on fucking me tonight.” 

Derek paused in his movements, tensing up like he was worried he’d done something wrong, but Stiles was still talking. 

“That’s so fucking hot, fuck, I need your fingers in me _now_.” 

Isaac took his dick back in hand and shivered in anticipation as Derek slicked up his fingers. Stiles moaned when Derek pushed one into him and Isaac had to press his hand against his mouth to keep from moaning along with him. 

“I love how soft you are inside,” Derek said quietly. “You feel so good.” 

“You can’t say things like that, ’s not fair.”

“No? I can’t say how amazing you feel around my fingers? Around my cock?” 

“No," Stiles said, and Isaac could smell the sweat building on his skin. "Definitely not."

Derek slid another finger in along the first, pumping them slowly in and out. “I can’t tell you how well we fit together? Or how much I like the way you look at me when I’m inside you?” 

Stiles pushed at Derek’s shoulder with his foot. “Oh my god, I hate you, I’m so turned on right now I can’t even think. Stop teasing me.” 

“You want me to stop talking?” 

“Yes! No- I… _Derek_ ,” Stiles whined. 

“It’s okay,” Derek soothed, pulling his fingers out. He nuzzled the base of Stiles’ dick, stroked it for him until Stiles relaxed. “You’re so hard for me and I’m gonna make you come so hard, okay? You ready?” 

“Yeah, I think so. Gimme the lube. And take your pants off, ‘cause you’re not fucking me with your jeans on.” 

Derek handed the bottle to Stiles and stood up. His jeans were hanging off his hips; he pushed them off, along with his boxers, exposing his tight, firm ass. 

“Stay like that,” Stiles said, wetting his hand with lube. He jacked Derek until his cock was dripping with it and Derek was pushing his hips forward to fuck into Stiles’ hand. Then Stiles lay back on the couch, spreading his legs. 

Derek didn’t climb on top of Stiles right away, like Isaac expected. Instead, he knelt down next to him, cupped the back of his head, and drew him into a kiss. Stiles responded eagerly and coaxed Derek up onto the couch until they were pressed against each other, naked and sticky with lube in inopportune places. 

Stiles was the one who broke the kiss, drawing away and waggling his eyebrows in a ridiculous manner that looked like some kind of code. Derek evidently knew the code. He sat back on his knees and pulled Stiles’ hips into his lap, guiding his dick with one hand until it was butting right up against Stiles’ asshole. 

“You’ll tell me if it hurts?” 

“You know I will,” Stiles said patiently, looking up at Derek and running a hand soothingly along his arm. “We’ve done this before, remember?” 

“I know, I just…” 

“You worry. It’s okay, I get it.” 

Now more than ever Isaac felt that he was intruding on something immensely private. This was a side of Derek he’d never seen before. He hadn’t known Derek could be like this; dirty-talking one minute and sweet and caring the next. It was a revelation. 

“I missed you,” Derek said.

“I know. I missed you too, and it totally sucks that right after we finally get together, my dad drags me off to, like, the middle of nowhere, to visit an aunt I didn’t even know we had- but I’m back now. I’m the same Stiles, just two weeks older, and I’d really like it if you’d fuck me. You won’t hurt me, I promise.” 

Derek didn’t say anything, but he rubbed his hand along Stiles’ hipbone and gave him a tiny smile, and Stiles smiled back, and that seemed to fix whatever was wrong, at least for now. Stiles lay back, loose-limbed and relaxed as Derek slowly pushed into him an inch at a time. When he was most of the way inside, with Stiles splayed out on his lap, Derek leaned down for a kiss. 

Isaac would never have guessed that Derek would be so into kissing, but it seemed like every chance he got, he was seeking out Stiles’ mouth. They kissed until Stiles started shifting his hips impatiently. That was when Derek sat up and made his first tentative thrust, holding Stiles still as he slipped the rest of the way inside. Isaac had a perfect view of the moment when Derek’s groin met flush with Stiles’ ass, and his dick dribbled clear precome at the quiet _oh_ Stiles let out. 

“Good?” Derek asked.

“Yeah, I’m good. C’mon, let me feel you. You know how they say _it’s not the size of the boat; it’s the motion of the ocean_?…” 

“You’re-” 

“Ridiculous, I know,” Stiles said, grinning. 

They shared another look between them, and then Derek pulled out a couple of inches, pushed back in, and they were fucking. 

Derek couldn’t get very good leverage or depth in their current position, but he didn’t seem to mind, content with making short little thrusts, his hands stroking up and down Stiles’ body, wandering over his sides, his nipples, the light trail of hair on his chest. Stiles had one hand on his cock and the other on Derek’s arm, looking up at Derek with half-lidded eyes as he touched himself. Neither of them spoke for a long time. 

“Want to ride me?” Derek panted eventually, and when Stiles nodded enthusiastically he slid his arms under Stiles’ shoulders and scooped him up in one smooth motion. 

Watching them, it was obvious that Derek was really into lap sex, just from the noises he was making. It was also far easier for him to kiss Stiles like this, which he was taking full advantage of. Stiles definitely liked it too, if the way he was rubbing his dick against Derek’s stomach and cupping Derek’s face to kiss him harder was any indication. 

Also? They’d clearly fucked like this before. Stiles’ motions were smooth and fluid, while the way Derek cupped his ass to help support his weight was too natural to be new to them. They settled into a rhythm quickly. Stiles steadily picked up the pace until his dick was slapping against Derek’s stomach and they were both too undone to kiss. 

“You close?” Stiles asked, the words almost lost amongst the heavy panting and sounds of fucking that filled the room. 

“Yeah…fuck, Stiles, I’m so close-” 

“I want you to come in me.” 

Derek gaped at him and so did Isaac. The way Stiles said it…Jesus. Was Isaac seriously about to watch Derek come in Stiles’ ass for the first time? 

“ _Fuck,_ ” Derek gasped out. 

Stiles hooked his arms around Derek’s neck to balance himself and rode Derek fast and hard. Derek’s hips came up to meet his every thrust. 

“Yeah, do it. Come in my ass.” 

Derek’s thrusts were getting increasingly uncoordinated until suddenly he stilled, moaned, and buried his face in Stiles’ shoulder. Stiles snuck a hand between them to get at his cock, jerking off even as he ground his hips down to wring the last of Derek’s orgasm out of him. 

“Fuck, I can feel it,” he moaned, and shot all over Derek’s chest, come landing as high as his nipples. 

Once they’d both had a moment to recover, Derek helped Stiles lift up and off his cock. Stiles pushed Derek down and sprawled on top of him and they shared a brief kiss.

“Gross, I think I’m leaking,” Stiles complained. “We’d better get up or I’m gonna stain the couch. 

“What- _Derek_ ,” he added, as Derek slipped two fingers between Stiles’ ass cheeks.

“I like it,” Derek said.

“Me too, but if I get your come all over the couch there are gonna be questions asked that we don’t want to answer, not yet. Lemme up so we can go shower.”

“You’re the one on top of _me_ ,” Derek pointed out.

“Yeah, well, you’ve got your fingers in my ass, so I’m pretty much at your mercy at the moment.” 

Derek sighed, and pulled out his fingers with a wet squelch.

“Shower,” Stiles said firmly. “I’ll let you wash me, if you want.” He got up and pulled Derek with him, leading him by the hand down the hallway.

“Tell me about your trip,” Isaac heard Derek say, and then the bathroom door shut and the water turned on and muffled Stiles’ reply.

Isaac looked down at his lap. He so wanted to take care of his erection here and now, but if he jerked off, Derek would _definitely_ be able to smell it. He made a face and gingerly tucked his dick back into his boxers and pulled up his jeans, trying to rearrange his junk into a semi-comfortable position. It would have to do until he could find someplace private to take care of himself.

The shower was still running as he crept out of the window seat and made for the door. With any luck, they’d never know he was here.

 

**Author's Note:**

> Thanks for reading, and please let me know what you thought!


End file.
